The manufacture of the lowest cost, highest performance version of an RF-ID system such that tags (transponders) could be disposable but also readable at approximately a meter distance, is oftentimes accomplished through the use of a capacitance circuit and antenna printed on a film, with a transponder IC mounted on top of the film, or just the antenna printed on the film, with a transponder IC mounted on the film, wherein the Transponder IC incorporates the capacitance of the resonant circuit. The Q of an antenna printed on film is dependent upon the number of turns (in addition to other factors), but what also is controlled by the number of turns is the effective inductance. In turn, the effective inductance, coupled with the capacitance of the resonant circuit, determines the resonant frequency.
The read range of the interrogator is dependent, in part, on the Q of the resonant circuit, because the higher the Q, the higher the read range. Another factor in determining read range is the sameness of the transponder response resonance frequency to the reader exciter frequency. In order to achieve the best possible reading/programming range the tag resonance frequency should be adjusted as close to the reader exciter frequency as possible. If the transponder resonant structure is comprised of inductor windings and capacitor blocks printed on some medium, i.e. film or foil, line width tolerances are not within the inductive and capacitive tolerances allowed. Therefore, some tuning of the transponder is necessary. Tuning in the most efficient and proficient way is the challenge.